Chapter 3 - Fuel System Components Adn Operation

Question 1

Fuel is stored in tanks which can be :

Answer 1

Integral
Metal
Flexible fabric membrane

Question 2

Fuel tank pressure requirement

Answer 2

Unpressurised iron pressurised with air

Question 3

Effect of altitude increase

Answer 3

Atmospheric air pressure decrease and boiling point of all liquids decreases

Question 4

Purpose of tank pressurisation and vent system

Answer 4

Maintain the pressure of air above the fuel at an appropriate level

Question 5

Air/ No fuel valve use

Answer 5

Prevents loss of fuel during inverted flight or AC climb

Question 6

Pressurised tanks advantages

Answer 6

Can transfer fuel between tanks

Prevents excessive fuel vapour

Reduces fire risk

Maintains shape of flexible tanks

Question 7

Pressurised tanks disadvantage

Answer 7

Added weight and routing complexity of additional components and pipework

Question 8

Tank pressurisation system components

Answer 8

NRV
PRV
Outward relief valve
Inward relief valve
Fuel/No air valve
Vent valve
Pressure switch

Question 9

Fuel supply components

Answer 9

Booster pumps
NRV
Low Pressure (LP) Fuel Filter
LP Fuel Cock

Question 10

Fuel cooled oil cooler (FCOC)

Answer 10

Surface type heat exchanger

Temp increase of fuel will prevent any water it may hold from turning to ice which could block the supply line

Question 11

Air Cooled Fuel Cooler (ACFC)

Answer 11

Cools fuel to prevent vapour locks and gum residues forming

Question 12

Ejector (jet pump)

Answer 12

Used with or alternatively to ACFCs - cool hot fuel by mixing with cold fuel prior to its return to a fuel tank

Question 13

Methods of fuel transfer

Answer 13

Air pressure
Electric transfer
Fuel ejectors
Gravity

Question 14

Air pressure transfer

Answer 14

Increasing pressure in a tank producing a force on the surface of the fuel that is used to push it through transfer pipelines to the next tank

Question 15

Electric Transfer pumps

Answer 15

Similar to booster pumps, fitted in pairs with a NRV on the outlet of each pump to prevent fuel being recirculated back into the tank if one pump fails

Question 16

Fuel ejectors (jet pumps)

Answer 16

Uses a small amount of fuel from the booster pump outlet directed to the fuel ejector nozzle

Question 17

Components for fuel tank level and transfer control

Answer 17

Float valve

Float switch

Question 18

Float valve

Answer 18

No electrical input, sense and control the transfer by automatically stopping flow when a specific level is reached

Question 19

Float switch

Answer 19

Positioned to sense a specific level and complete an electrical circuit, signal is then passed to fuel control system which controls tank level by sending signal to open or close valves or turn on or off pumps

Question 20

Purpose of fuel management and control

Answer 20

Maintain CG by managing transfer sequence

Provide indications of various parameters and warnings of malfunctions

Give crew various options in the movement of fuel and to counter any system malfunctions

Question 21

Methods of achieving control (automatically)

Answer 21

System design/layout

Electrical components

Mechanical components

Question 22

Fuel flow proportioners

Answer 22

Used to maintain balance by taking a specific amount of fuel from two or more sources and passing it to a common outlet

Question 23

Pipelines

Answer 23

Join various components in the aircraft systems to permit fluid flow between them.

Question 24

Fuel content purpose

Answer 24

To provide a continuous and accurate indication to the crew of the quantity of useable fuel on board

Question 25

List of indications given by fuel gauging system

Answer 25

Total fuel systems contents

Contents of individual tanks or group of tanks

Amount of fuel being used at any given time